Figure 1.

In vitro tests of the silk hydrogel Au-NP composite. a) Bactericidal effects observed in the central clear region where laser was applied (450 mW for 15 minutes, NP concentration 2.5x). Central clear zone, termed zone of inhibition (ZOI), indicates lack of bacterial presence, whereas surrounding turbid area represents a bacterial lawn. b) IR camera images of the temperature map at the end of laser application. Temperature scale bar in °C. c) Overlay of a) and b). Black circle: ZOI; graph: temperature profile of dashed white line, solid red shading (>50°C) corresponds to ZOI region. d) ZOI for various laser power (exposure time 15 minutes, NP concentration 2.5x). e) ZOI for various durations of laser exposure (600mW, 2.5x NP). f) Maximum temperature achieved for various NP concentrations (laser power 450mW, exposure time 10 minutes) and the corresponding g) maximum temperatures for several laser exposure times. h) Edge-on view of a slab of porcine meat injected with NP+Gel (40x concentration) at a depth of 2 mm below the surface. Laser (150 mW) was applied for 10 minutes to the surface layer directly above injection sites. Temperature maps for 2 mm and 5 mm cases at the end of exposure to laser. Ruler next to slab in mm, dashed white line represents slab surface, black dashed circles correspond to injection sites, temperature scalebar in °C.